First‑Line Oral Muscle Relaxant for Acute Neck Pain

Recommendation

Cyclobenzaprine 5 mg three times daily for up to 14 days is recommended as the first‑line oral muscle relaxant for adults with acute neck pain (≤2 weeks), when no contraindications exist. The American Geriatrics Society guideline cites consistent efficacy data and a favorable sedation profile at this dose. 1

Tizanidine 2 mg up to three times daily may be used when cyclobenzaprine is not tolerated; it has fair evidence of benefit for acute musculoskeletal pain but requires monitoring for muscle weakness, orthostatic hypotension, and drug‑drug interactions. 4
Methocarbamol can be considered as a secondary option, although supporting evidence is more limited. 2

Carisoprodol should be avoided because it is a controlled substance with abuse potential, withdrawal risk, and limited analgesic benefit. The American Geriatrics Society advises against its use. 5
Metaxalone, chlorzoxazone, and orphenadrine have insufficient evidence of efficacy for acute neck pain and are not recommended. 2

The evidence for muscle relaxants in acute neck pain is limited to short‑term therapy (≤2 weeks); no data support effectiveness for chronic neck pain. 3
Cyclobenzaprine’s benefit is modest but statistically superior to placebo; central nervous system adverse events occur about twice as frequently as with placebo (risk ratio ≈ 2.0). 3

Common adverse effects of cyclobenzaprine include dry mouth, constipation, dizziness, and mild somnolence; these are generally self‑limited. 6
Because cyclobenzaprine is structurally similar to the tricyclic antidepressant amitriptyline, it carries anticholinergic risks (e.g., urinary retention, blurred vision). 6
Older adults are at higher risk for falls and anticholinergic side‑effects; dose reduction and close monitoring are advised. The American Geriatrics Society highlights these concerns. [1][6]

Muscle relaxants should be prescribed as part of a multimodal regimen (e.g., combined with NSAIDs and activity‑preserving advice) rather than as monotherapy. 3
Therapy should be limited to the acute phase; discontinuation is recommended after 7–14 days if no clear benefit is observed. 3

If a true muscle spasm is suspected, agents that directly affect spasticity such as baclofen (starting 5 mg three times daily) or short‑acting benzodiazepines may be considered, with careful titration and awareness of withdrawal risk. [6][7]
Cyclobenzaprine should be held on the day of any surgical procedure to avoid peri‑operative sedation and interaction with anesthetic agents. 5